1. Field of the Invention
The invention relates to a proximity printing device in which exposure is performed by irradiation of a workpiece with light which has passed through a mask. The invention relates especially to a proximity printing device in which the angle of the light with which the workpiece is irradiated can be changed.
2. Description of Related Art
The production of electrical and electronic components and parts of various types in which processing of structures in the micron range is necessary utilizes an exposure process. These electronic parts are semiconductor components, liquid crystal display devices, multi-chip modules, etc., in which a host of diverse electronic components is produced on a substrate, and thus, a module and the like is formed.
As one of the exposure systems in the above described exposure device, a proximity printing system is used in which irradiation is performed with parallel light in a state in which there is a small gap between a mask and a workpiece. In the proximity printing system, the advantage is that, as a result of the absence of contact of the mask with the workpiece, the mask is less contaminated, and thus, has a longer service life than in a contact printing system.
FIG. 8 schematically shows the arrangement of a proximity printing device. In the figure, a light irradiation device 10 is shown which comprises a discharge lamp 1, which emits light which contains UV radiation (such as a super high pressure mercury lamp) or the like, an oval focusing mirror 2, a first mirror 3, an integrator lens 4, a shutter 5, a second mirror 6 and a collimator 7.
The light which is emitted from discharge lamp 1, which contains UV light, is focused by means of the oval focusing mirror 2, reflected by first mirror 3, and is incident in integrator lens 4. The light emerging from the integrator lens 4 is reflected, furthermore, via shutter 5 by second mirror 6 and emerges from light irradiation device 10 via collimator 7.
Furthermore, a mask carrier 11 is provided on which a mask M is seated and attached, as is a workpiece carrier 12 on which a workpiece W is seated and attached, a gap adjustment device 12a and a X-Y-Z-.theta. carrier 13.
An alignment microscope AM is provided by which mask alignment marks MAM of mask M and workpiece alignment marks WAM of the workpiece W are observed and alignment of mask M and workpiece W is performed. Accordingly, irradiation with light which contains UV light from the light irradiation device is produced via the mask.
X-Y-Z-.theta. carrier 13 is driven by means of a carrier drive device (not shown) and which moves the workpiece carrier 12 in the X-Y-Z-.theta. directions (X: to the right and left in FIG. 8, Y: forward and backward in FIG. 8; Z: up and down in FIG. 8, .theta.: in the direction of rotation around an axis perpendicular to the workpiece carrier surface).
Gap adjustment device 12a is positioned to set mask M and workpiece W parallel to one another with a given gap. This can be done using the gap adjustment device disclosed commonly owned, published Japanese patent application HEI 7-74096, or the like.
In the following, exposure of the workpiece W is described with reference to FIG. 8.
First, the mask M is set and attached at a fixed location of mask carrier 11. Next, the workpiece carrier 12 on which workpiece W is placed is moved down by the drive of the X-Y-Z-.theta. carrier 13. Then, the workpiece carrier 12 is moved up by the drive of X-Y-Z-.theta. carrier 13 so that workpiece W comes into contact with mask M. Afterwards, the workpiece W is moved further upward. In this way, the gap adjustment device 12a is displaced and the total area of mask M comes into contact with workpiece W, by which the inclination of the mask M agrees with the inclination of the workpiece W.
Next, while maintaining the displaced state of the gap adjustment device 12a, the X-Y-Z-.theta. carrier 13 is driven and workpiece carrier 12 is moved downward a fixed distance. In this way, the mask M and the workpiece W are set parallel to one another and with a constant gap relative to one another.
After adjustment of the gap between the workpiece W and mask M to a constant value, alignment microscope AM is used to observe mask alignment marks MAM recorded on mask M and the workpiece alignment marks WAM recorded on workpiece W. Driving of X-Y-Z-.theta. carrier 13 moves workpiece carrier 12 in the X-Y-Z-.theta. directions so that the positions of mask alignment marks MAM are brought into agreement with the positions of workpiece alignment marks WAM. The light which contains UV light is emitted onto mask M from light irradiation part 10, and thus, workpiece W is exposed.
However, recently there has been a need for exposure by irradiation of a workpiece W.sub.A with a wiring pattern in a stepped area using light which contains UV radiation, as shown in FIG. 9A. Similarly, a need has arisen for exposure by irradiation of workpieces W.sub.B having a three-dimensional arrangement using light which contains UV radiation, as is shown in FIG. 9B.
In the case of exposure by irradiation of the above described workpieces with light which contains UV radiation, the stepped areas cannot be exposed to a sufficient degree, even if the mask is irradiated vertically with light.
This means that, in the case of exposure of workpieces with stepped areas, the stepped areas or the perpendicular surfaces cannot be exposed to a sufficient degree if the light is not obliquely emitted, as is shown in FIGS. 10(a) and 10(b).
In the above described conventional proximity printing device, light irradiation device 10 is located in a fixed position above mask carrier 11 and X-Y-Z-.theta. carrier 13. Oblique irradiation of the surface of mask M and the surface of workpiece W with light which contains UV radiation is therefore impossible. Therefore, the above described need cannot be met.